Accessing a JSON var wthout using item.item = string

Question

Here is the array

var weekdayColor = {
        sunday : 'red',       // sunday
        monday : 'blue',      // monday
        tuesday: 'white',     // tuesday
        wednesday: 'black',    
        thursday: 'green',     
        friday: 'yellow',  
        saturday: 'orange'     
    }

I want to be able to do something along the lines of weekcayColor[0] to get sunday:

Here is the JavaScript I wrote for an interview which was already turned in.. I know there is an easier way to do this. The first var weekdayColor CANNOT BE CHANGED; also weekdayColor.sunday returns red.

Perhaps I am using the wrong date method or accessing the var incorrectly?

var weekdayColor = {
        sunday : 'red',       // sunday
        monday : 'blue',      // monday
        tuesday: 'white',     // tuesday
        wednesday: 'black',     // wednessday
        thursday: 'green',     // thursday
        friday: 'yellow',    // friday
        saturday: 'orange'     // saturday
    }
    var weekday=new Array();
        weekday[0]="sunday";
        weekday[1]="monday";
        weekday[2]="tuesday";
        weekday[3]="wednesday";
        weekday[4]="thursday";
        weekday[5]="friday";
        weekday[6]="saturday";
    d = new Date;
    day = d.getDay();
    console.log(weekday[day]);
    a = weekday[day];
    function change(){
        var x = document.getElementById("weekday");
        x.innerHTML = a;
        x.style.color = weekdayColor[a];
    }

I believe it's fine because JavaScript Objects don't necessarily keep a cross-browser property ordering. So, you still need the weekday array for mapping. A bit of better formatting, code clean-up and usage of [] notation for array creation may have been better. — Alexander
– Alexander, Commented Jan 27, 2013 at 20:28
You can't access a JSON object property by an index value: http://stackoverflow.com/a/4231336/674700. — Alex Filipovici
– Alex Filipovici, Commented Jan 27, 2013 at 20:50
@AlexFilipovici You are confusing terms here. There is no such thing like JSON Object. Javascript has either Objects or Arrays (or simple datatypes like strings, number or booleans). JSON means javascript object notation and is a datatransfer format which bases upon javascript's object notation und thus is easily integrated into JS because if you parse it, you have a valid JS Object you can work with. — Christoph
– Christoph, Commented Jan 28, 2013 at 9:47

charlietfl · Accepted Answer · 2013-01-27 20:47:05Z

0

Not 100% sure what you are trying to do. If you just want to change today element color need to modify change() as follows:

function change(day){
    var x = document.getElementById(day);       
    x.style.color = weekdayColor[day];
}
var d = new Date(),
    day = d.getDay(),
    a = weekday[day];

/* now call change passing day as argument*/
change(a);

DEMO: http://jsfiddle.net/rhHjn/1

edited Jan 27, 2013 at 20:47

answered Jan 27, 2013 at 20:42

charlietfl

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Comments

Christoph · Accepted Answer · 2013-01-28 10:55:35Z

0

Easier would be to use an array of objects as following:

var weekday = [
   {name:"sunday",color:"red"},
   {name:"monday",color:"blue"},
   // and so on
]

Then you can do something like this:

d = new Date();
day = d.getDay();
weekday[day].name  // yields name
weekday[day].color // yields color

Alternatively you could write a prototype method:

Date.prototype.getDayName = function() {
return ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday']
       [this.getDay()];
}

and now

var d = new Date;
d.getDayName(); // this would actually give you the name of the day

edited Jan 28, 2013 at 10:55

answered Jan 27, 2013 at 20:51

Christoph

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2 Comments

Xeo Over a year ago

I can't change the initial var

Christoph Over a year ago

@Xeo You cannot access the keys of an object via Array Notation [i] because object keys are not ordered! Other than iterating over all properties of the object e.g. via a for loop you cannot tell, which keys it actually contains.

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